PARIS – A novel coronavirus that has killed more than half of the 38 people it is known to have infected appears capable of limited human-to-human spread, the World Health Organization said Sunday.

France reported a second case of the disease on Sunday. The patient, who is hospitalized in an isolation ward, probably caught the pneumonia-causing virus from an infected patient in a hospital room they shared in Valenciennes in late April, the Health Ministry and the WHO said Sunday.

The French cases have opened up a new front in an international effort to control the virus, which is related to the one that caused severe acute respiratory syndrome (SARS) a decade ago. The majority of infections with the new virus have occurred in Saudi Arabia, where on Sunday the Ministry of Health reported 15 deaths from 24 confirmed cases since September. Several of the infections have been tied to health care centers.

“The different clusters seen in multiple countries increasingly support the hypothesis that, when there is close contact, this novel coronavirus can transmit from person to person,” WHO spokesman Gregory Hartl said in a statement. “This pattern of person-to-person transmission has remained limited to some small clusters, and so far there is no evidence that this virus has the capacity to sustain generalized transmission in communities.”

Saudi Arabia has invited scientists from Columbia University to help with a field and environmental survey and also other specialists from Canada, the U.S. and the WHO, the Saudi Ministry of Health said.

“The emergence of this new coronavirus is globally recognized as an important and major challenge for all of the countries which have been affected as well as the rest of the world,” Hartl said.

Investigators have yet to determine the source of the virus, the mode of transmission, the level of human involvement in its spread or how widespread it is, he said.

Most of the infected people have been older men, often afflicted with other medical conditions, Hartl said. Doctors are not sure of the reason for this pattern and whether it will change over time, he said.

“Several urgent actions are needed,” Hartl said. “The most important ones are the need for countries, both inside and outside of the region, to increase their levels of awareness among all people, but especially among staff working in their health systems and to increase their levels of surveillance about this new infection.”

Coronaviruses are a family of pathogens that cause illnesses ranging from the common cold to SARS, which sickened more than 8,000 people and killed 774 in 2002 and 2003, according to the WHO. The new virus appears to be far less transmissible than SARS, WHO has said.